1. Field of the Invention
The present invention generally relates to the field of digital microscopy and more particularly relates to the focusing of a line scan camera prior to and during the capture of imagery data from a specimen on a microscope slide.
2. Related Art
In conventional virtual microscopy systems, image tiling techniques produce individual image tiles that can be significantly out of focus over much of the image. An image tiling system is restricted to a single focal distance for each individual snapshot taken by its camera, thus, each of these “fields of view” have areas that are out of focus when the subject specimen being scanned does not have a uniform surface. At the high magnification levels employed in virtual microscopy, specimens with a uniform surface are extremely rare.
Conventional image tiling solutions are severely handicapped by these limitations, with their only recourse being to discard a significant amount of out of focus image data, resulting in an increased number of image tiles that must be scanned and a corresponding increase in the time to scan a microscope slide. Even so, the resulting image data still suffers from out of focus areas on each image tile. The discarding of perimeter image data that is extremely out of focus still leaves out of focus image data in the image tile resulting from the inherent circular optical distortion.
Recently, new line scan camera systems have been introduced to the virtual microscopy industry such as the ScanScope® scanner created by Aperio Technologies, Inc. The revolutionary ScanScope® scanner system does not suffer from circular optical distortion due to its use of a line scan camera. Additionally, the line scan camera can adjust its focus for each line of pixels that are captured when scanning a microscope slide. Thus, the quality of the resulting image from a line scan camera system is significantly better due to the sharp focus of each line of pixels captured by the line scan camera.
Accordingly, these significant advancements in the virtual microscopy industry have created a need for a system and method that overcomes the significant focusing problems inherent in conventional image tiling systems and capitalizes on the focusing capabilities of the revolutionary line scan camera systems.